Background: Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study).
Methods: The study included baseline data collected in 1981 through 1983 on 10,955 persons age 40 to 79 years and baseline data collected in 1991 through 1994 on 7212 persons age 40 to 79 years. We used hospital diagnosis data from the Danish National Hospital Discharge Register to determine the rate of first hospital admission for atrial fibrillation during 7 years following each of the 2 baseline data collecting periods. Changes in admission rates were analyzed using Cox proportional hazard models.
Results: During the 2 7-year periods, 379 subjects were admitted with a hospital diagnosis of atrial fibrillation. The rate of hospital admissions for atrial fibrillation increased among both men and women from the first to the second period (relative risk = 1.6; 95% confidence interval = 1.3-1.9 [adjusted for age, sex, prior myocardial infarction, arterial hypertension, diabetes mellitus, electrocardiographic left ventricular hypertrophy, decreased lung function, smoking, height, and weight]).
Conclusion: During the latest 10 to 20 years, there has been a 60% increase in hospital admissions for atrial fibrillation independent of changes in known risk factors. This increase could result from changes in admission threshold or coding practices, or it could reflect a genuine increase in the population incidence of atrial fibrillation.